Process of dissolving cellulose



UNITED STATES PATENT OFFlCE.

ZENO OSTENBERG, OF SAN JOSE, CALIFORNIA, ASSIGNOR TO INTERNATIONAL CELLU- LOSE COMPANY, OF RENO, NEVADA. A CORPORATION OF NEVADA.

PROCESS OF DISSOLVING CELLULOSE.

Specification of Letters Patent.

Original application filed January 31, 1916,. Serial No. 75,356. Patent No. 1,218,954, dated March 13;

1917. Divided and this application filed November 1. 1916.

To all whom it may concern:

Be it known that I, ZENO Us'rnNnnno, a

citizen of the United States, and resident of San Jose, in the county" of Santa Clara and State of California, have invented a certain new and useful Improvement in Processes of Dissolving Cellulose, of which the following is a specification.

My invention relates to the process of roducing solutions of cellulose by dissolving cellulose in suitable mixtures of hydrochloric and sulfuric acids, or hydrochloric and phosphoric acids. this application being a divisional application of my Patent No. 1,218,954, March 13, 1917.

The use of highly concentrated hydrogen chlorid solution in the process of dissolving cellulose renders that process somewhat expensive, and the use of the gas to form the concentrated acid renders the process inconvenient, complicated. undesirable and. expensive. In my improved process I obviate the necessity of using hydrogen chlorid in the gaseous form by substituting therefor concentrated sulfuric or phosphoric acid.

Hydrochloric acid of a lower concentration than the acid of commerce (35.5% to 37 HCl) may be utilized in the same way by the addition of suflicient concentrated sul furic acid. In fact acids ranging in concentration from 25% HUI to 39% HCl have been utilized by me. Solutions of cellulose up to 17% in concentration may be obtained by dissolving the cellulose in the proper acid mixture. The greater the concentration of hydrochloric acid the greater is the amount of cellulose dissolved. T he solutions ob tained are useful in the arts and sciences since the cellulose may be recovered. in a number of Ways or it may be allowed to hydrolize and the glucose formed by hy drolysis may he recovered or fermented to alcohol. The mode of application. of these acid mixtures is varied depending on the re sult desired.

The following examples are merely illus trative and in no Way are to be understood as limiting my patent but will serve to make clear some of its uses. The acid mixtures are made by mixing concentrated acids of commerce in vessels sup )lied with suitable means for cooling. n utilizing hydrochloric acid of commerce for producing a solvent for cellulose I have found that 1% Serial No. 128,962.

parts of concentrated sulfuric acid is approximately equivalent to 1 part of hydrogen chlorid when dissolved in the commercial hydrochloric acid.

Example 1: One kilogram of airdried.' cotton is kneaded with about six kilograms 0 of a mixture of 9 parts hydrochloric acid (37% E01) and 1 part of concentrated sulfuric acid by weight. If hydrogen chlorid should escape the solution is suitably cooled. A thick viscid mass results which may be clarified and then forced through orifices into a suitable coagulating fluid, as Water, dilute acid, solutions of various salts and various other media.

Example 2: Comminuted Wood is intimately mixed with a sufiicient quantity of a 1 part concentrated sulfuric acid9 parts hydrochloric acid (37% HCl content) mix ture so that the amount of water present does not exceed one-fifth of the weight of cellulose or cellulose derivatives present in the Wood. A portion of thecellulose dissolves and hydrolyzes at room temperature and more cellulose goes into solution and this also hydrolyzes until finally all of the cellulose is converted into dextrose (glucose). A considerable amount of the Water is used up in the process and this causes a disengagement of hydrogen chlorid. As much as possible of the hydrogen chlorid is recovered directly, the mass extracted by a suitable solvent, as Water. and the remainder of the acid IGIIiOYQd completely as possible by osmosis.

The solutions of sugars (dextrose and pentoses) may then be used in the arts.

Example 3: 1} kilogram. of comminuted Wood is kneaded with about six kilograms of a mixture of 9 parts hydrochloric acid (37% HCl) and 1 part of concentrated sul furic acid by weight. If hydrogen chlorid should escape the solution is suitably cooled. A thick viscid mass results from which the lignin is filtered oil. and then forced through orifices into a suitable coagulating fluid. as water, dilute acid, solutions of various salts and various other-media.

lnthe term cellulose is included the socalled. o'xycelluloses and hydrocelluloses and ligno-ccllulose. Lignin is insoluble in the acid mixture used and is left undissolved when such material as wood is used as a cellulose containing material.

I claim:

1. T he process of dissolving cellulose in a mixturu of tiOllCUIlU'illfbll hydrochloric acid and (UiHOIltl'tllfit'l sulfuric acid at u temperature hulo'w 5i) (1.

2. In the process nil dissolving; LQllUlOSG in highly concentratecbhydrochloric acid the 11: placement of part of the liyilrucliloi'ic :mirl by sulfuric acid at a tun'iperzitxiu'e holuw 50 C.

3. The: pruccss (if (lism'ilving cellulose in a mixture of l'LYLlIOCl'llULlC acid and sulfuric acid with an initial uniuunt of Water not to QXCGQH onwfifth of the Weight of the cellulose at IL tmnperuturc below 50" C.

4-7 In the. process of vlissolvil'lg cellulose in highly coiuzuiitratvd liyilriuchlnric acid the n-plmm111em' uf purt'ul" the l'iyilrocliloric acid by uulittchtrtktml sulfuriv avid at; a ratio of ll parts of mncentrated sulfuric acid. to take the place of one part of hydrogen him-id at a temperature below 50" C.

In testimony whereof I have hereunto all fixed my signature this 26th dayof October. 1916.

ZENO ObTENBERG 1b is hereby certifivd that Lmlm's lfiatout N0. 1,:34SJ31, granted August 3, i920, upon the applicutivn of Zvnu Osu-nbcrg, of Sm: Jase, .luli'idmia, for an improvement in Processes of Dissulving Usallnlusu. were nrroneuusly issued to International Cellulose Company as sssiguufl of t-hn entire interest in said invention, whereas said Lethal-s Patent, should luv-e. biwn issued to the in'ventor, said ()stenbe-rg, as sole mvner of said invention; and that the said Let-tersfatent. shouJd be read with this correction therein that. the same may conform to the record of thecnse in the Patent Office.

Signed and sealed this 14th day oi September, A. D., 1920.

[SEAL] M. H. COULSTON,

Acting Commissioner of Patents. 

